The results from epidemiologic and animal studies strongly suggest that environmental lead exposure is associated with an elevated prevalence of dental caries. Although there has been a recent decline in caries prevalence in some segments of the population, the distribution of caries in the population is skewed, with the majority found in urban, minority communities. Populations from such communities are also at risk for elevated blood lead levels. Human studies show an association between lead exposure and caries, but have not controlled for some possible confounders. Animal studies indicate lead may adversely affect tooth structure, mineralization of enamel, and salivary function. One study shows that lead-exposed rats have more caries than controls; of note, the average blood lead level of the exposed rats was 8 mug/dL, a blood lead level defined to be acceptable in humans. If this association is also true for humans, it suggests that the current prevalence of lead exposure may pose a public dental health problem. The overall goal of this proposal is to derive preliminary data regarding the association between lead exposure and caries in children; specific aims are: a) to compare the distribution of lead exposure among children who have caries to children who are caries-free; b) to estimate the dose-response relationship between lead exposure and caries; c) to estimate the odds ratio for caries among children with lead exposure as compared to children without lead exposure. The study utilizes a nested case-control design. Lead exposure is defined as one blood lead level collected: a) between age 18 to 36 months and, b) via venipuncture phlebotomy, or via fingerstick phlebotomy and with a blood lead level lesser 10 mug/dl; blood lead levels will be obtained from an archive of blood lead levels at the local county health department. From an on-going school-based caries screening program, we will identify children age 4 to 7 years with caries (i.e., cases) and children without caries (i.e., controls). Cases will be frequency matched to control by age, gender and school site. Among children having appropriate blood lead levels to define lead exposure, we will subsequently collect data on the following potential confounding variables: a) oral hygiene (by determining plaque scores); b) diet; c) cariogenic bacteria (by culturing saliva); e) fluoride exposure. This study, by controlling for specific confounders, will aid in establishing whether there is an association between lead exposure and caries.